Imaging devices having piezoelectric transceivers
A micromachined ultrasonic transducer (MUT). The MUT includes: a substrate; a membrane suspending from the substrate; a bottom electrode disposed on the membrane; a piezoelectric layer disposed on the bottom electrode and an asymmetric top electrode is disposed on the piezoelectric layer. The areal density distribution of the asymmetric electrode along an axis has a plurality of local maxima, wherein locations of the plurality of local maxima coincide with locations where a plurality of anti-nodal points at a vibrational resonance frequency is located.
1. A micromachined ultrasonic transducer (MUT), comprising:
a substrate;
a first electrode coupled to the substrate, wherein the first electrode that is symmetric with respect to a first axis and asymmetric with respect to a second axis that is normal to the first axis, the first axis extending along a direction where the first electrode has a longest dimension, the second axis passing through a midpoint between two ends of the first electrode on the first axis; and
a second electrode coupled to the substrate and non-co-planar with the first electrode,
wherein the first and second electrodes are separated from one another in a vertical direction, and
wherein the first electrode comprises a top electrode and the second electrode comprises a bottom electrode.
2. The MUT of claim 1 , wherein the MUT is a capacitive micromachined ultrasound transducer (cMUT).
3. The MUT of claim 1 , wherein the MUT is a piezoelectric micromachined ultrasound transducer (pMUT).
4. The MUT of claim 3 , further comprising:
a membrane suspending from the substrate;
a piezoelectric layer;
wherein the first and second electrodes are disposed on the piezoelectric layer.
5. The MUT of claim 4 , wherein the piezoelectric layer is formed of at least one of PZT, KNN, PZT-N, PMN-Pt, AIN, Sc-AIN, ZnO, PVDF, and LiNiO3.
6. The MUT of claim 1 , wherein the first and second electrodes are separated from one another along a third axis normal to both the first and second axes.
7. The MUT of claim 4 , wherein the first electrode is disposed on a first side of the piezoelectric layer and the second electrode is disposed on a second side of the piezoelectric layer facing a direction opposite the first side.
8. An imaging device, comprising:
a transducer array including a plurality of micromachined ultrasonic transducers (MUTs),
each of the plurality of MUTs comprising:
a substrate;
a first electrode coupled to the substrate, wherein the first electrode is symmetric with respect to a first axis and asymmetric with respect to a second axis that is normal to the first axis, the first axis extending along a direction where the first electrode has a longest dimension, the second axis passing through a midpoint between two ends of the first electrode on the first axis; and
a second electrode coupled to the substrate and non-co-planar with the first electrode,
wherein the first and second electrodes are separated from one another in a vertical direction, and
wherein the first electrode comprises a top electrode and the second electrode comprises a bottom electrode.
9. The imaging device of claim 8 , wherein each of the plurality of MUTs is a capacitive micromachined ultrasound transducer (cMUT).
10. The imaging device of claim 8 , wherein each of the plurality of MUTs is a piezoelectric micromachined ultrasound transducer (pMUT).
11. The imaging device of claim 8 , wherein each of the plurality of MUTs further comprises:
a membrane suspending from the substrate;
a piezoelectric layer,
wherein the first and second electrodes are disposed on the piezoelectric layer.
12. The imaging device of claim 11 , wherein the piezoelectric layer is formed of at least one of PZT, KNN, PZT-N, PMN-Pt, AIN, Sc-AIN, ZnO, PVDF, and LiNiO3.
13. The imaging device of claim 8 , wherein the first and second electrodes are separated from one another along a third axis normal to both the first and second axes.
14. The imaging device of claim 11 , wherein the first electrode is disposed on a first side of the piezoelectric layer and the second electrode is disposed on a second side of the piezoelectric layer facing a direction opposite the first side.
15. A micromachined ultrasonic transducer (MUT), comprising:
a substrate;
a first electrode coupled to the substrate, wherein the first electrode that is symmetric with respect to a first axis and asymmetric with respect to a second axis that is normal to the first axis, the first axis extending along a direction where the first electrode has a longest dimension, the second axis passing through a midpoint between two ends of the first electrode on the first axis;
a second electrode coupled to the substrate and non-co-planar with the first electrode; and
a piezoelectric layer,
wherein the first and second electrodes are disposed on the piezoelectric layer,
wherein the first electrode is disposed on a first side of the piezoelectric layer and the second electrode is disposed on a second side of the piezoelectric layer facing a direction opposite the first side.
16. The MUT of claim 15 , wherein the MUT is a capacitive micromachined ultrasound transducer (cMUT).
17. The MUT of claim 15 , wherein the MUT is a piezoelectric micromachined ultrasound transducer (pMUT).
18. The MUT of claim 15 , further comprising a membrane suspending from the substrate.
19. The MUT of claim 15 , wherein the piezoelectric layer is formed of at least one of PZT, KNN, PZT-N, PMN-Pt, AIN, Sc-AIN, ZnO, PVDF, and LiNiO3.
20. The MUT of claim 15 , wherein the first and second electrodes are separated from one another along a third axis normal to both the first and second axes.
21. An imaging device, comprising:
a transducer array including a plurality of micromachined ultrasonic transducers (MUTs),
each of the plurality of MUTs comprising:
a substrate;
a first electrode coupled to the substrate, wherein the first electrode is symmetric with respect to a first axis and asymmetric with respect to a second axis that is normal to the first axis, the first axis extending along a direction where the first electrode has a longest dimension, the second axis passing through a midpoint between two ends of the first electrode on the first axis;
a second electrode coupled to the substrate and non-co-planar with the first electrode; and
a piezoelectric layer,
wherein the first and second electrodes are disposed on the piezoelectric layer,
wherein the first electrode is disposed on a first side of the piezoelectric layer and the second electrode is disposed on a second side of the piezoelectric layer facing a direction opposite the first side.
22. The imaging device of claim 21 , wherein each of the plurality of MUTs is a capacitive micromachined ultrasound transducer (cMUT).
23. The imaging device of claim 21 , wherein each of the plurality of MUTs is a piezoelectric micromachined ultrasound transducer (pMUT).
24. The imaging device of claim 21 , wherein each of the plurality of MUTs further comprises a membrane suspending from the substrate.
25. The imaging device of claim 21 , wherein the piezoelectric layer is formed of at least one of PZT, KNN, PZT-N, PMN-Pt, AIN, Sc-AIN, ZnO, PVDF, and LiNiO3.
26. The imaging device of claim 21 , wherein the first and second electrodes are separated from one another along a third axis normal to both the first and second axes.